The usefulness of my advice depends on the size of your mother's portfolio. If she has say, 10 year's spending needs, I recommend that she keep about three years requirement in a money market fund, and replinish it every two years depending on the level of the market. If the market is in a tailspin, she should wait for a recovery even if it takes a full year.

As for allocation of her investments, I strongly recommend all stocks or an index fund. Bonds are historically poorer performers than stocks.

Adhering to a set formula may make one feel that they are taking a scientific approach to investing, but in my opinion, all you need are common stocks (or an index fund) and cash in a money market. I live by my own advice. I have been retired for three years.

Best wishes, Bill Rogers